外源激素对大花蕙兰组织培养的影响

以茎尖为外殖体进行大花蕙兰组织培养,研究表明：大花蕙兰茎尖在MS＋6-BA1.5mg/L＋NAA0.1mg/L培养基上培养25d后,茎尖分化形成原球茎;原球茎在1/2MS＋6-BA2.0mg/L＋NAA0.1～0.2mg/L培养基上增殖速度最快,增殖系数可达7.62;原球茎在1/2MS＋NAA0.2mg/L培养基上分化最好,分化的大花蕙兰幼苗在1/2MS培养基上生根效果好。     

芽变毛白杨组织培养初步研究

以芽变毛白杨幼嫩枝条为外植体进行愈伤组织和茎段组织培养试验研究。结果表明:芽变毛白杨诱导愈伤组织培养基为:MS 6-BA 2.0~4.0 mg/L 2,4-D 1.5~2.0 mg/L NAA 0.25 mg/L KT 2.0~4.0 mg/L 3%蔗糖,愈伤组织分化芽培养基为MS 6-BA 0.5 mg/L NAA 0.5 mg/L KT 2.0 mg/L 3%蔗糖时,培养效果好。茎段培养时,适宜无根苗生长的培养基为MS 6-BA 0.5 mg/L NAA 0.1 mg/L 3%蔗糖,生根诱导适宜的培养基为1/2MS IBA 0.5~1.0 mg/L 1.5%蔗糖。     

驱蚊草组培快繁技术研究

以驱蚊草幼嫩茎段为外植体,将其接种在MS BA2.0mg/L 2,4-D0.2mg/L培养基上进行培养,15~20天嫩茎诱导形成愈伤组织,诱导率达90%,然后将愈伤组织接种于MS BA1.0mg/L 2,4-D0.5mg/L的培养基中进行培养,15天左右开始形成丛生芽,最后将成苗接种于1/2MS NAA0.5 mg/L培养基中,7~10天生根率可达100%。     

彩叶朱蕉组织培养育苗技术研究

以彩叶朱蕉优株顶芽和茎段为外植体,设计不同浓度细胞分裂素、生长素以及培养基组合,诱导芽分化、增殖和生根.MS+6-BA 3.0 mg/L+NAA 0.01 mg/L+蔗糖30g/L培养基适用于诱导芽的形成,3/4MS+6-BA 2.0 mg/L+NAA 0.01 mg/L+蔗糖30g/L培养基适用于芽的增殖,3/4MS...     

齿瓣石斛原球茎诱导及植株再生技术试验

对齿瓣石斛原球茎诱导及植株再生技术试验的结果表明:齿瓣石斛原球茎最佳诱导培养基为MS+6-BA3.0 mg/L+NAA0.1 mg/L;增殖分化培养基为MS+6-BA 2.0 mg/L+NAA0.5 mg/L;壮苗生根培养基为MS+IBA1.0 mg/L+NAA0.1 mg/L。     

不同激素组合对鸡冠花离体快速繁殖的调控

该文对不同激素组合对鸡冠花愈伤组织诱导、芽的分化以及苗的快速繁殖进行了研究。结果发现子叶、子叶节较易诱导愈伤组织,叶腋较难诱导愈伤组织。接种鸡冠花无菌苗的子叶节、子叶于附加6-BA2~3mg/L+NAA0.2mg/L的MS培养基上,获得了芽的快速增殖,形成芽簇,每丛2~6苗。将切下的苗接种于MS培养基上,6d开始生根,获得完整再生植株。     

优良观赏植物银边绣球的培组织养技术

选用优良观赏植物银边绣球(Hydrangea macrophylla var.蔭cula-ta)健壮幼嫩茎尖作为组培试验材料进行组培技术的研究。结果表明:诱导愈伤组织形成的培养基组合为MS+BA2.0mg/L+NAA0.1mg/L,有利于愈伤组织生长;不定芽分化的培养基为MS+BA2.0mg/L+NAA0.1mg/L有利于不定芽的分化;而4/5MS+BA2.0mg/L+NAA0.1mg/L有利于组培苗不定根的形成。     

文心兰组织培养研究

以茎尖为外殖体进行文心兰组织培养,研究表明：文心兰茎尖在MS＋6-BA5mg/L＋NAA0.2mg/L培养基上培养40d后,茎尖分化形成原球茎;原球茎在MS＋6-BA2.0mg/L＋6-BA5mg/L＋NAA0.1-0.2mg/L培养基上增殖速度最快,增殖系数可达7.25;分化的文心兰幼苗在1/2MS＋NAA0.5mg/L生根效果最好。水草为文心兰组培苗驯化栽培最佳基质。     

大花、重瓣型非洲紫罗兰组织培养技术研究

对大花、重瓣型非洲紫罗兰(Saintpaulia ionantha)的组织培养研究表明,外植体消毒以0.1%的升汞溶液浸泡5~6 min为宜;不同激素浓度对其愈伤组织诱导、愈伤组织分化、芽丛形成及根的形成有不同的影响;生长素与细胞分裂素的比例决定着愈伤及芽丛的形成;小苗在1/2MS培养基上生根最好。各培养阶段的最适培养基分别为:愈伤组织诱导MS+6-BA1.0 mg/L+NAA 0.5mg/L,芽分化及增殖培养MS+6-BA 2.0 mg/L+NAA0.5 mg/L,生根培养1/2MS+NAA0.1 mg/L或1/2MS+IBA0.1 mg/L。     

乌腺金丝桃茎尖离体培养基激素配比筛选

为寻求乌腺金丝桃的高效人工繁殖方法,以乌腺金丝桃茎尖作为外植体,筛选初代诱导、继代增殖、生根培养3个阶段的最佳培养基激素配方。结果得出,把经过消毒后的乌腺金丝桃茎尖切割成0.3 mm、周围带2~3个叶原基,转入MS+6-BA 3.0 mg/L+NAA 0.1 mg/L+LH 500 mg/L培养基,分化率达到100%,能诱导出大量的健壮不定芽;然后将这些不定芽切割成1 cm小段转入MS+6-BA 2.0 mg/L+IBA 0.2 mg/L+GA_3 1.0 mg/L培养基,增殖效果最好;经过2~3次的继代增殖后,将增殖的大量苗木切割成2 cm小段转入到1/2 MS+IAA 0.2 mg/L生根培养基中,生根效果最佳,平均根数达到4.6,且根系粗壮,有利于今后出瓶移栽。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.